armbrust



Sept. 11, 1962 J. c. ARMBRUST 3,053,399

ARM BLOCK-UP DEVICE Filed Dec. 24, 1958 5 Sheets-Sheet 1 IN VEN TOR.

Sept. 11, 1962 J. c. ARMBRUST 3,053,399

ARM BLOCK-UP DEVICE Filed Dec. 24, 1958 3 Sheets-Sheet 2 E ii Elli! 1N VEN T OR.

United States Patent Ofilice 3,5l53fl99 Patented Sept. llll, 1%62 3,053,399 ARM BLOCK-UP DEVICE Joseph C. Armbrust, Marion, Ind, assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed Dec. 24, 1958, Ser. No. 782,788 2 Claims. (Cl. 214-1) This invention relates to materials handling apparatus and in particular to devices adapted for application to such apparatus so that such apparatus may be safely serviced and repaired. The invention is particularly adapted for use with materials handling machines which include a swinging pendant arm usually provided at its lower end with gripping means to handle sheet metal blanks or stampings to be inserted and removed from stamping presses. Apparatus for which the present invention is particularly adapted is shown for example in United States Patent 2,609,776 issued to Henry Sahlin, September 9, 1952. As shown by that patent such apparatus includes a pendant swinging arm which on occasion must be blocked up out of the way for various reasons such as servicing or repairing the stamping press or working on the arm and the control means therefor. At the present time it requires two men to either block up or unblock a materials handling arm such as shown by the Sahlin patent. One man is required to hold a tryout button which operates the control apparatus for raising and lowering the arm while a second man climbs up the arm or press and then changes the block up arm to either hold the arm up or to release it. During this block-up operation, a safety stop button may be pressed or a safety block joy plug may be pulled, the press selector switch may be changed or any electrical failure might cause the arm to drop and possibly injure the employee attempting to either block the arm up or unblock it. The present invention is proposed to eliminate the likelihood of injury during this block-up operation.

The present invention has also been proposed to eliminate the need for two men to perform the block-up operation. The present invention utilizes an unusual latch assembly which may be first pre-set by an operator who then raises the arm which automatically cams back the latch so that upon slight lowering of the arm by its hydraulic means it engages the upper side of the latch and is held in the raised position. After the repair or maintenance work has been completed, to lower the arm the operator sets the block-up device so that a bias is placed on the latch tending to withdraw it from below the materials handling arm. It is not withdrawn, however, because of the weight of the arm resting thereon. Then as the operator operates the arm to again raise it by its hydraulic operating means, the latch is withdrawn and the arm is free to swing downwardly and perform its normal operating functions.

For a fuller understanding of the invention and the objects thereof, reference may be made to the detailed description and drawings in which:

FIGURE 1 is a view in elevation of a stamping press having combined therewith a materials handling arm and hand and the novel block-up device applied thereto.

FIGURE 2 is a view somewhat enlarged also in elevation taken on the line 22 of FIGURE 1 further illustrating details of the materials handling arm and hand and also the details of the block-up device applied thereto.

FIGURE 3 is a side elevational view showing the arm held in its raised position by the unique block-up device.

FIGURE 4 is a detail view taken on the line 44 of FIGURE 5 showing how the operating portion of the block-up device is locked in position to maintain a bias on the latch so that when the arm is raised by its hydraulic operating means the latch will be biased or cammed inwardly out of the plane of movement of the arm so that the arm may be lowered.

FIGURE 5 is a detail view taken on the line 5-5 of FIGURE 3 illustrating most of the details of the unique block-up device and shows the latch holding the operating arm in the raised position.

FIGURE 6 is a View similar to FIGURE 5 except that the block-up device has been Set to bias the latch out of the plane of movement of the materials handling arm.

Referring now to the figures and particularly to FIG- URES l and 2, a stamping press indicated generally by a numeral 2 is shown. The stamping press 2 includes a press table 4- and a press ram 6 movable with respect to each other by suitable hydraulic and mechanical means indicated by numerals 8 and It whose details will not be discussed further inasmuch as they form no part of the present invention. Located between the tabel 4 and the ram 6 are the stamping blanks or work pieces 12 which are located between these two members by the materials handling arm and hand indicated generally by a numeral 14. The arm 14 is pivotally supported on guide members 16 adapted to be raised and lowered on the vertical guides 18 by suitable hydraulic means such as Zti, etc. The lower end of the arm 14 is provided with a hydraulically operated mechanical hand or gripper 22 while is adapted to remove or insert the blanks or stampings I2 between the ram and table of press 2. It will be noted that as the guide members to move vertically on the guides 18, the arm 14 by reason of rollers 24 on crank ends 26 thereof engaging the curved cammed surfaces 28 will swing upwardly in addition to moving vertically upwardly. Thus it may be appreciated that swinging and vertical movement of the arm is controlled by suitable hydraulic means at the disposal of the operator of the press or some other person. There are occasions, however, when it is desired to have the operating arm 14 maintained in its upper position as indicated in FIGURE 3 so that work may be done on the table or rarn of the press or perhaps on the materials handling arm 14. In such cases as previously indicated, it has been the practice to block the arm up by one person operating the hydraulic controls for the arm and another person climbing up on the press or the arm and fixing a block under the arm to some suitable support. In view of the many things that can go wrong, such as the operator who is controlling the arm inadvertently operating the controls in a wrong manner or hydraulic or electrical failures, this procedure is extremely dangerous and in many cases is likely to result in injury to the person attempting to perform the actual block-up operation. It is for these reasons that the present invention has been proposed.

Referring now to all of the figures and particularly to FIGURES 1 and 2, the unique block-up device is shown fixed as by studs or welding to the support means for the materials handling arm and hand and is indicated generally by a numeral 30. The block-up device 30 comprises a frame made up of a pair of plates 32, and 34 spaced by spacers 36 and 38 welded therebetween. 'Pivotally hung between the plates 32, 34 on pin 40 is a latch 42 which includes a h0ok-line catch 44 at its lower end. The latch 42 is proportioned and weighted so that in its free state it tends to hang in the position shown in FIG- URE 5. Also secured between the plates 32 and 34 is a tubular member 46 in which is located a helical coil spring 43 and a plunger 50 having a stem 52 extending within the spring 48 and having a shoulder 54 engaging the upper end of spring 43. Telescoped within the tubular member 46 nearer the lower end 56 thereof is a plunger-like member 58 which is also provided with a stem 60 extending within the lower end of spring 48. The member 58 is provided with a stud 62 which is adapted to move upwardly and downwardly in a slot 64 in member 46. An operating handle 66 is suitably fastened to the lower end of member 58. It will be noted that the upper end 68 of plunger 50 is adapted to engage an arm 70 on the latch 42. The catch 44 of latch 42 is cut on a bias as indicated at 72 so that when the arm 14 is moved upwardly it will cam catch 44 out of the plane of movement of the arm. The operation of the block-up device 30 is as follows:

Assuming first of all that it is desired to block up the arm for any of a number of reasons such as to maintain or repair the arm or the press, the operator first would pre-set handle 66 in its lowermost position as seen in FIG- URE 5. He would then Operate the hydraulic operating means for the arm to move it to an upper position. As the arm moves upwardly, it will engage the surface 72 of catch 44 of latch 42 and will cam the latch out of the plane of movement of the arm so that the arm will rise above catch 44. As the arm moves above catch 44, however, the weight of latch 42 will cause it to return to the position shown in FIGURE 5. Subsequent lowering of the arm will cause it to engage the upper side of catch 44 so that the arm is now safely blocked up out of the way without danger of falling upon any personnel working on the arm or the press (see FIGS. 3 and 5). Once the work has been'completed and it is desired to lower the arm, the handle 66 is pushed upwardly so that the stud 62 moves upwardly in the slot 64. The handle is then turned slightly so that the pin 62 moves through a horizontal slotted portion 74 and into a detent slotted portion 76 where it will be retained. Movement of the handle 66 upwardly to the position just described will load spring 48 and consequently plunger 50 and also the latch 42 tending to cause it to turn clockwise when viewing FIGURE 5. Because of the weight of the arm 14, however, on catch 44, the latch 42 will remain in the position shown in FIGURE 5 until the arm is again further raised by its hydraulic operating means. As the arm is raised the latch 42 will move inwardly between plates 32, 34 (see FIG. 6) and the catch 44 will move out of the plane of movement of the arm 14 so that the arm may now be lowered. The handle 66 and latch 42 will remain in the position of FIGURE 6 for normal use of the arm 14. If the operator again wishes to block up the arm, he must remove the bias from the spring 48 by slightly raising the handle 66 so that the pin 62 moves out of the detent position and can be slightly turned and consequently lowered along the slot 64 thereby removing the bias from spring 48. This will allow the plunger 50 to move downwardly in the tubular member 46 and accordingly by reason of the weighting of latch 42 it will move out from between the plates 32, 34 so that the catch 44 again lies in the plane of movement of arm 14.

From the foregoing description it should now be appreciated that the unique block-up means herein described adds to the safe maintenance and repair of materials handling equipment such as materials handling arms and hands and further enables the block-up function to be simply and easily accomplished by one person.

I claim:

1. In combination, a support, a swinging work arm pivotally hung on said support, and means for releasably holding said arm in a raised position comprising a latch pivotally mounted on said support, said latch having a hook on a free lower end thereof weighted so that the said hook hangs in the plane of swinging of said arm, the

' underside of said hook being formed on a bias so that engagement of said hook by said arm by raising thereof cams said hook out of the plane of swinging of said arm, means for raising said arm above said hook and lowering said arm onto said hook to hold said arm in a raised position, and biasing means operable to bias said hook from ing a support and a latch pivotally supported thereon having a cam catch in the plane of movement of said arm whereby said arm may be raised above said catch and engaged thereby to prevent lowering thereof, and biasing means operable to bias said catch out of the plane of movement of said arm so that said arm may be lowered, said biasing means comprising guide means on said support, a spring-loaded plunger in said guide means having an end engaging a projection on said latch, a handle guided by said guide means and engaging the spring of said plunger and operable to apply a bias of said spring and plunger against said projection, and means for 1ocking said handle in a position of bias by said spring of said plunger.

References Cited in the file of this patent UNITED STATES PATENTS 1,593,315 Story July 20, 1926 2,201,179 Jackson May 21, 1940 2,609,776 lSahlin Sept. 9, 1952 2,677,342 Miller May 4, 1954 2,849,084 Hott et a1. Aug. 26, 1958 

